rao_soft27

 Profile Answers by rao_soft27 

• Jul 9th, 2007

 

VoiceXML interpreter contexts, just like HTML visual browsers, can use caching to improve performance in fetching documents and other resources: audio recordings (which can be quite large) are as common to VoiceXML pages as images are to HTML pages.

The default caching policy for VoiceXML interpreter contexts is one commonly employed in HTML browsers:

If the document referenced by a URI is unexpired in the cache, then use the cached copy.

If the document referenced by a URI is expired or not present in the cache, then fetch it from the server using
'get'. Note: it is an optimization to perform a 'get if modified' on an expired document still present in the cache.

In VoiceXML this caching policy is known as 'fast'. But because fast cache usage can lead to anomalous results, VoiceXML browsers also implement a
'safe' caching policy:

Even if the document referenced by a URI is in the cache and is unexpired, still do a
'get if modified' operation. This will force a more recent version of the document to replace the cached version, if a more recent version exists. If no more recent version exists, the server does not go to the expense of transferring the document.

If the document referenced by a URI is expired or not present in the cache, then fetch it from the server using
'get'. Note: it is an optimization to perform a 'get if modified' on an expired document still present in the cache

VoiceXML allows the author to select which caching policy to use. The
'caching' attribute in the element can be set to 'safe' or 'fast' to determine what default policy to use for that document. If this attribute is not specified, the
'fast' policy is used.